MASS EXTINCTION: All life on Earth went extinct 252 million years ago

Nearly all
life on Earth became extinct 252 million years ago. According to
Massachusetts Institute of Technology, or MIT scientists, the culprit
was not an asteroid striking the planet, but a methane-spewing microbe.

The Permian-Triassic extinction has been defined as a natural event that heated up the Earth's biological systems.

"When one examines old rocks that were deposited at the time, the results of those geochemical analyses indicate that there was a large influx of carbon into the Earth's system - that is, the oceans and the atmosphere - and that carbon likely entered system as CO2," Rothman says.

The massive change happened in the "geological blink of an eye;" about 60,000 years, which killed 96 percent of life in the ocean and 70 percent of life on land. This era was known as the Permian-Triassic extinction event. In more concrete terms, the Great Dying.

The carbon dioxide that erupted from volcanos was a potent greenhouse gas. The process warmed the air and turned oceans acidic. Rothman now says that the volcanic activity in what is today Siberia cannot solely account for the global geo-chemical change.

"It's a gross correlation, and the question is how it might be related," he says. "It's not the only question, but it is the one of the questions we address in our paper."

An analysis of the genomic record that revealed a marine microbe that produces methane and could be an important player in the massive die-off.

"Methane-producing microbes had already been present, but this was a particular microbe that could do it a little bit more efficiently than the others," he explains. "And so we've hypothesized that it might have been responsible for the outburst of carbon into the system - originally methane - and the methane would have been oxidized to CO2."

Rothman and colleagues report that the methane microbes experienced an explosive growth which was fueled by the mineral nickel, which they found in sedimentary rocks from those Siberian eruptions.

The nickel concentrations rose considerably just before extinction, which would have made a very favorable environment for the methane-producing microbes.

The Permian-Triassic extinction has been defined as a natural event that heated up the Earth's biological systems.

"It's not that unusual in the history of life for such things to occur," Rothman says. "The point is that life and the environment interact. They always have and they always will."